In the field of computer vision, image features of an image must be accurately extracted to obtain better processing results. However, in actual applications, due to the effect of weather etc., even the image of a same object taken in different weather appears to have different image features. Refer to FIG. 1, which shows four images of Tiananmen taken on a clear day, a smoggy day, a rainy day and a snowy day respectively.
In prior art, during the extraction of the image features of the four images mentioned above, a same image feature extraction method is generally applied to extract the image features without considering the effect of weather in which the image was taken on the image feature extraction. This may sometimes lead to failure of the image feature extraction and further affect subsequent various computer vision applications dependent on the results of the image feature extraction.
Therefore, in order to improve the image feature extraction and to be able to extract image features with respect to the weather in which the image was taken, it is necessary to identify the weather in which the image was taken before extracting image features.